Document state_cache

[spaceone]

Hi,

I searched for state_cache in the documentation (https://pysaml2.readthedocs.io/en/latest/search.html?q=state_cache&check_keywords=yes&area=default#) without results.

I think it would be good to document this feature.
I assume Saml2Client's state_cache and identity_cache are the only in memory stored data which need to exist between multiple requests?!

An example how to use this with multiprocessing would be good.
Maybe https://pypi.org/project/shared-memory-dict/ helps.
Maybe also an example for memcached as well.

[spaceone]

I also found in the docs for subject_data that it is possible to store things in memcached: https://pysaml2.readthedocs.io/en/latest/howto/config.html?highlight=memcached#subject-data
As subject_data is in the chapter including service providers, I don't know where/when this is used. Or is this only for IDP's?

[peppelinux]

AFAIK I never used it, I'm sorry I can't help you